DULWICH COLLEGE SHANGHAI
SCIENCE DEPARTMENT
NAME:______DATE:______
IGCSE - PHYSICS
Energy
Answer all questions in the spaces provided.
Use full working for all calculations.
Take acceleration due to gravity to equal 10m.sˉ2
1. A 2.0kg toy car is moving with a velocity of 4.00m.sˉ¹ and a toy truck with a mass of 4.00kg is moving at 2.00m.sˉ¹. Determine which vehicle has the greatest:
(a) Kinetic energy.
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4 MARKS
(b) If both vehicles started at 0.00m.sˉ¹ determine the work being done to get them to the velocities mentioned above. You must explain the reason for your answer to receive full marks. Assume there is no friction.
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2 MARKS
2. A large dam is place 650m above a natural valley and supplies water to a hydro-electric power station that is 60m above the valley. If 4000kg.sˉ¹ of water gushes through the power plant, determine the amount of electrical energy produced per second if the plant is 80% efficient.
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5 MARKSAAI 2/14
3. Choose one form of energy generation that was discussed in class and explain the processes involved in generating the electricity. Be sure to consider its renew ability and effects on the environment.
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4 MARKS
4. A computer is an example of an energy converter. It converts electrical energy into other forms. List two forms of energy that this electrical energy is converted into within a computer.
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2 MARKS
5(a). Explain the “Law of the Conservation of Energy”.
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2 MARKS
5(b). Scientists have been trying to develop a “Perpetual Motion Machine” (a machine that never stops moving once it starts) for a long time, however, this has proven to be impossible. Explain why this dream is impossible.
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2 MARKS
6.(a) Explain the changes in energy that occurs as a tennis ball is dropped from a height of 1.5m until just before it hits the ground.
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2 MARKS
(b) Explain why the ball does not return to 1.5m after it bounces.
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2 MARKS
7. A weight lifter at the recent Beijing games lifted a 120kg bar above her head, a distance of 2m. The lift took 1.5s to complete.
(a) Calculate the work done by the weight lifter.
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3 MARKS
(b) Calculate the power generated by the lifter during this lift.
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2 MARK
8. Three students decided to go on a camping trip on the DCS playing field. As it is the depths of winter they decided to light a fire on the cricket pitch. When they did this they noticed a cold breeze blowing onto there backs. Explain this phenomenon.
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3 MARKS
9. Many homes in cold climates like Beijing use double glazing in their windows. Explain why this technique is effective in reducing the amount of thermal energy lost from homes during winter.
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3 MARKS
10. The Western Australian Cricket Team’s colours are black and gold. Explain why they have elected to play in a uniform that is mainly gold with some black rather than the opposite way around. (Cricket is a summer sport)
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3 MARKS
End of paper.